I. Field of the Invention
This invention relates generally to cardiopulmonary test equipment, and more particularly to apparatus for conveying a respiratory gas mixture breathed by a patient to the gas analyzer apparatus in which water vapor is effectively extracted from the mixture during its flow from the patient's mouthpiece, mask or head.
II. Discussion of the Prior Art
In equipment of the type disclosed in the Anderson, et al. U.S. Pat. No. 4,463,764 and assigned to applicant's assignee, various parameters to be measured include the partial pressure of CO.sub.2 and O.sub.2 contained in a breath sample. Where measurements are to be performed on a breath-by-breath basis, it is essential that the volume of the sample tube used to convey the expiratory gas mixture to the analyzer be kept as small as possible to provide a short transport time and to minimize distortion of the waveform. Moreover, it is desired that the gas sample be dry, i.e., free of water vapor by the time it reaches the analyzer. While in-line desiccators may be effective to remove moisture from a gas stream flowing therethrough, such devices, to be effective, must be of a size wherein the volume involved no longer accommodates breath-by-breath analysis.